1. Field of the Invention
This invention relates to an exhaust valve for a bag for compressing its content to be compact. The exhaust valve is fitted to the bag for containing bedclothes such as a comforter, a blanket or the like. The inside of the bag is de-aerated by using a suction nozzle of a vacuum cleaner or the like.
2. Description of the Prior Art
When a comforter, cloths, or the like is stored in a closet or a chest, it is a conventional practice that the comforter or the like are put into a flat bag made of synthetic resin, and the air inside the bag is removed out of the bag by using a vacuum cleaner to compress the content, so that a limited space of storage may be used to store as many comforters, cloths or the like as possible. Compression of the contents like this has been done not only in general homes but also in traders and manufacturers involved in beddings. Further, the bag is also compressed when cloths or the like is packed in a bag when traveling.
When the bag containing a comforter or the like is compressed, it is usual that part of an opening part of the bag is opened by a fastener provided at the opening part of the bag, which is de-aerated by a suction nozzle of the vacuum cleaner inserted into the bag from its opening part. However, when the suction nozzle is directly inserted into the bag, the content of the bag may be sucked into the opening end of the suction nozzle by a suction force of the nozzle. Consequently, not only the content may be damaged but also the suction nozzle is plugged up making de-aeration of the bag difficult and causing a failure of the vacuum cleaner because of the heavy load imposed on its motor.
Therefore, it is known to fit the exhaust valve to the bag in advance, through which the air in the bag is exhausted from outside by using the suction nozzle of the vacuum cleaner to compress the bag, without inserting the suction nozzle into the bag.
The exhaust valve as mentioned above is known from Japanese Patent Publication 2003-34379 for example in which the exhaust valve comprises a valve body provided with an exhaust opening in its center, which exhaust opening connects with the inside of the bag, and a dome-shaped movable lid having a suction opening in its center which suction opening goes through the upper and the lower surfaces of the movable lid. The movable lid is mounted onto the valve body to be freely movable up and down. The exhaust valve further comprises a valve plate for opening and closing the above-mentioned exhaust opening, a spring for keeping the valve plate in close contact with the exhaust opening by pressing the valve plate from the above, and a valve plate operating mechanism for moving the valve plate up to open the valve against the spring force, all of which are positioned inside a chamber formed between the facing surfaces of the movable lid and the valve body. The valve plate is opened by means of the valve plate operating mechanism, which is operated by pressing down the movable lid. With this state, the air inside the bag is exhausted through the suction opening by using the suction nozzle of the vacuum cleaner. After exhausting the air, the valve plate operating mechanism is locked so that it may not move.
However, according to the structure of the exhaust valve as mentioned above, there is a problem that the bag is swollen. Namely, the mechanism for locking the valve plate operating mechanism against movement comprises guide projections mounted onto several parts of the outer periphery of the valve body, and arc-shaped long openings formed in several peripheral parts of the movable lid. The upper ends of the guide projections are inserted into the arc-shaped long openings so that the movable lid may be moved downwardly. The mechanism also comprises engaging projections each of which are mounted to be integrated one with an end of each of the arc-shaped long openings. When the movable lid is turned to a position where each of the engaging projections faces the upper part of each of the guide projections, the engaging projections are received by the guide projections so that the movable lid may be prevented from moving downwardly. Therefore, when excessive load is imposed on the movable lid due to piling up of the bags or the like, the engaging projections are damaged causing failure of locking, the consequence of which is that the movable lid is moved downwardly causing of the bag to swell.
In addition, when the inside of the bag is de-aerated, it is necessary to maintain a state of opening of the valve plate against the spring force by pressing the suction nozzle of the vacuum cleaner against the movable lid. Not only is such an operation troublesome but also it is inconvenient. Moreover, because the spring is formed of metal, it may be rusted and smooth operation may become impossible.
Further, even after the bag is de-aerated completely, the suction force of the vacuum cleaner is applied to the inside of the bag through its suction nozzle, whereby its motor is loaded heavily and a failure of the vacuum cleaner may be caused. To solve the problem, an opening for taking the outside-air is formed in the peripheral part of the movable lid. As mentioned above, the movable lid is formed to be a dome-shape so that the suction nozzle of the vacuum cleaner may be pressed against any part of the movable lid not only in a perpendicular direction but also in an inclined direction. Therefore, when the suction nozzle is moved to slant widely on the movable lid in front, rear, right and left directions, it may depart from the suction opening.
Furthermore, the valve body of the exhaust valve comprises a disc-shaped base plate having an exhaust opening formed in its center, and a valve-positioning member provided with the valve plate for opening and closing the exhaust opening. The base plate and the valve-positioning member are put onto the outside and the inside surfaces of a part of the bag, respectively, in a state that the part of the bag where a vent is formed is sandwiched between them in a unified manner. Consequently, when the exhaust valve is opened and the air inside the bag is suctioned and removed from the vent through the exhaust opening, the suction force is applied intensively to the surface of the content beneath the exhaust opening. Thus the surface is sucked to the exhaust opening by the powerful force. Consequently, not only is a comparatively long time required before finishing de-aeration of the inside of the bag, but also excessive load is imposed on the motor of the vacuum cleaner, causing a failure of the vacuum cleaner.
These problems of the known valve as mentioned above cannot be solved even in such a structure that exhaust air passages of a predetermined height are radially provided to project on the lower surface of the base plate of the valve body from the periphery of the exhaust opening toward the outer peripheral edge of the base plate, because the surface of the content of the bag around the opening of the exhaust air passages comes into close contact with the inner surface of the bag by the suction force coming through the exhaust air passages. When the content has less air permeability such as a down quilt, it is difficult to exhaust the air through the fine weave pattern of the bagging.
To solve the problem, it is so structured that a porous plate having a predetermined thickness is mounted on the lower surface of the base plate outwardly from the outer peripheral surface the base plate to be unified, so that a space as large as the size of the porous plate may be provided between the surface of the content and the inner surface of the bag. However, because each of the pores has a pore wall having a predetermined height corresponding to the thickness of the porous plate and is formed to be an independent vent, which is prevented from communicating with the adjacent pores, suction force cannot be smoothly applied to the vent through the exhaust opening. Consequently, the above problems are not solved completely.